1. Field of the Invention
The present invention relates to a suspension system for steered wheels in a vehicle, and particularly to a steering wheel suspension system which is capable of distributing different driving forces or braking forces to the left and right steered wheels suspended by left and right suspensions.
2. Description of the Related Art
FIG. 11 diagrammatically shows a vehicle having a front engine and front drive which is being turned. King pin axes K.sub.L and K.sub.R, which are steering centers of left and right steered wheels W.sub.FL and W.sub.FR that are driven wheels, are offset inwards of a vehicle body with respect to ground points G.sub.L and G.sub.R of the left and right steered wheels W.sub.FL and W.sub.FR. Therefore, center offsets OS.sub.L and OS.sub.R exist between the king pin axes K.sub.L and K.sub.R and the ground points G.sub.L and G.sub.R. If driving forces T.sub.L and T.sub.R of the engine are applied to the left and right front wheels W.sub.FL and W.sub.FR, a moment M.sub.L (M.sub.L =T.sub.L .times.OS.sub.L) intending to steer the left front wheel W.sub.FL in a clockwise direction (a turning direction) about the king pin axis K.sub.L is applied to the left front wheel W.sub.FL, which is an outer wheel during turning of the vehicle, and a moment M.sub.R (M.sub.R =T.sub.R .times.OS.sub.R) intending to steer the right front wheel W.sub.FR in a counterclockwise direction (a direction opposite from the turning direction) about the king pin axis K.sub.R is applied to the right front wheel W.sub.FR, which is an inner wheel during turning of the vehicle.
However, in the conventional front engine and front drive vehicle, the driving force of the engine is distributed equally to the left and right front wheels W.sub.FL and W.sub.FR through a differential. Moreover, the left and right center offsets OS.sub.L and OS.sub.R are set equally to each other and, hence, the steering moment M.sub.L for the left front wheel W.sub.FL, which is the outer wheel during turning of the vehicle, is balanced with the steering moment M.sub.R for the right front wheel W.sub.FR, which is the inner wheel during turning of the vehicle. Therefore, there is no problem in that a steering wheel is not unintentionally turned outwards or inwards during turning of the vehicle because of the steering moments M.sub.L and M.sub.R.
In a vehicle in which, for example, in clockwise turning of the vehicle, a larger driving force T.sub.L is distributed to a left front wheel W.sub.FL, which is an outer wheel during turning of the vehicle, and a smaller driving force T.sub.R is distributed to a right front wheel W.sub.FR, which is an inner wheel during turning of the vehicle, in order to enhance the turning performance of the vehicle, the steering moment (M.sub.L =T.sub.L .times.OS.sub.L) for the outer wheel is larger when the steering moment (M.sub.L =T.sub.R .times.OS.sub.R) for the inner wheel, resulting in a problem of the generation of a so-called, "counter-action" phenomenon of steering wheel, in which the steering wheel is unintentionally turned inwards of the direction of turning of the vehicle due to a difference between the steering moments M.sub.L and M.sub.R.